Bipolar limiter with additional differential winding



P 1 J. w. THOMPSON 1,776,205

BIPOLAR LIHI'IER WITH ADDTIIONAL DIFFERENTIAL WINDING Filed March 1, 1929 was . 24. D f /V 710%? Atzor/Ley Patented Sept. 16, 1930 UNITED STATES JOHN W. THOMPSON, OF PUEBLA, MEXICO 3120mm LIMITER WITH ADDITIONAL DIFFERENTIAL WINDING Application filed March 1,

vention by the device illustrated in the accompanying drawings, in which,-

Figure 1 is a diagrammatic view of my invention when the connections of the circuit are normal 5 Fig. 2 is a similar illustration showing the position of the device when the flow of current is increased, that is, when more load is connected in;

Fig. 3 is a similar View illustrating conditions when a client has made a false ground;

and

Fig. 4 is a similar view showing conditions when a client has inverted the connections of the supply and connected what was the phase side of the load to a false ground.

Like characters of reference designate like parts in each of theseveral views.

Referring to the accompanying drawings, I provide two solenoids mounted one above the other and having a common core 14. The upper solenoid is composed of two equal windings A and B connected differentially in the circuit in orderto produce the magnetic fluxes in opposite instantaneous directions. The lower solenoid has two equal windings C and D, these, however, being connected so that their fluxes are accumulative. VVindings A and C are connected in series with each other by the wire 19, as are also windings B and D which are connected by the wire 26. The plunger 14 comprises two pieces of magnetic material 29 with a junction piece and a small section at the top, each of non-magnetic material and designated 30.

The circuit is broken when the plunger 14 is attracted upwards and strikes the pivotally mounted, preferably L-shaped lever 5 which is constructed of non-conducting material with two inserts 6 and 7 of conducting the lower half of the plunger.

1929. Serial No. 343,811.

material, these inserts serving as bridges across the contacts. I The limiter functions in the following manner: When the connections of the circuit are normal the current flows from the. source 51 through the wire 15 and across the contacts 32 and insert 6 to the wire 17 which in turn connects with the wire 18 constituting the winding A and thence through wire 19 to the wlre 20-which constitutes the winding (J and thence through wire 21 to the load 22 and returning'fthrough wire '23 to the wire 24, which constitutes the winding D and thence through wire 25'-to-the wire 27, which constitutes the winding B, and thence through wire 28 to the contacts 33 and insert 7 to the wire 16 to the ground H.

WVhen the load does not exceed the value for which the limiter is adjusted the magnetic field is not strong enough to suck up the plunger. When more load is connected in, the pull'of the connected windingsovercomes the weight of the plunger, which moves upward and strikes the lever, interrupting the circuit. :Note the dotted line illustration in Fig. 2.

7 When the connections are correct the magnetic fluxes produced by the windings A and have instantaneous directions, neutraliz-' 1 ing each othcr, and hence do not affect the plunger which'only functions by the attractions of th'e windings C and B.

Coils A and B in F i 1 form one solenoid separate and distinct from solenoid formed by coils'C and D. These two solenoids are separated by a sufficient distance, one above theoth'er, 'so as not to have any mutual effect. Thus the actionof coils A and B of the upper solenoid is confined to the upper half ofthe 'plunger,'while' the actionof the two coils C and D of the lower solenoid is "confined to In practice the two coils of each' solenoid "are wound'on the same spool, one outside of the other, forming 'a'bobbi'n about one inch in diameter by one and a half inches long, and the two bobbins thus formed are separated from each other three-quarters of an inch,

which" has been found suflicient to prevent any mutual-action; 1 ii 7 If the client makes a false ground, windings B and D are shunted, the current returning through the false ground to the line H which is the ground neutral of the system. As winding B is now shunted, the fluxes produced by winding A is no longer counterbalanced, hence winding A assists winding C in pulling up the plunger of the solenoid. As soon as the circuit is interrupted the magnetic attraction ceases and the plunger falls back and closes the circuitonce more, where'- upon the process is repeated. This operation of the device is illustrated in Fig. 3.

lVhen the overload is exceptionally excessive the plunger is sucked up with such force as to cause the lever to engage with the end 9 of the claw 10, interrupting the circuit until such time as the button 12 is pressed, thus releasing the engagement of the claw, which is mounted on pivot 11, from the end 8 of the L-shaped lever 5.

In the event of the client inverting the connections of the supply and connecting what was the phase wire of the load to a false ground X, windings A and C are thus shunted, as shown by the dotted lines in Fig. a. WVindings B and D cause a similar set of operations to take place as above described. lVith the new limiter which I have devised fraudulent connections cause an interruption of the circuit thereby preventing the customer securing current which does not pass through the limiter.

that I claim is:

1. In a device for the purposes described,

' the combination of an L-shaped lever of nonconducting material, said lever having inserts of conducting material at each end thereof, one of the ends ofthe lever being hook shaped, two solenoids arranged one above the other and each having two equal windings, a plunger functioning as a. common core for the solenoids and consisting of two pieces of magnetic'material with a top and intermediate section of non-magnetic material and connecting sections of magnetic material, the plunger being positioned directly beneath the insert of conducting material in the upper arm of the L-shaped lever, an,

electric connection from a source of current to the insert in the upper arm of the L-shaped lever, an electric connection from the insert to the upper winding of the upper solenoid, an electric connection between the upper windings of the respective solenoids, a separate electric connection between the lower windings of the respective solenoids, electric connections from the lower solenoid t0 the load, an electric connection from the lower winding of the upper solenoid to the lower conducting insert of the L-shaped lever and an electric connection from the said insert toa. ground, a hook member adapted to engage the end of the upper lever arm when same is thrown to raised position by the plunger of the solenoids to break the circuit whereby to hold the lever in such position to stop the flow of current, and a button in operative engagement with said hook device for permitting an authorized person to release same from engagement with the L- shaped lever.

2. In a device for the purposes described, the combination of an L-shaped lever of nonconducting material, said lever having inserts of conducting material at each end thereof, two solenoids arranged one above the other and each having two equal windings, a plunger functioning as a common core for the solenoids and consisting of two pieces of magnetic material with a top and intermediate section of non-magnetic material and connecting sections of magnetic material, the plunger being positioned directly beneath the insert of conducting material in the upper arm of the L-shaped lever, an electric connection from a source of current to the insert in the upper arm of the Lshaped lever, an electric connection from therinsert to the upper winding of the upper solenoid, an electric connection between the upper windings of the respective solenoids, a separate electric connection between the lower windings of the resoective solenoids, electric connections from the lower solenoid to the load, an electric connection from the lower winding of the upper solenoid to the lower conducting insert of the L-shaped lever and an electric connection from the said insert to a ground, a hook member adapted to engage the end of the upper lever arm when same is thrown to raised position by the plunger of the solenoids to break the circuit whereby to hold the lever in such position to stop the flow of current, and a buttonin operative engagement with said hook device for permitting an authorized person to release same from engagement with the L-shaped lever.

3. In a device for the purposes described, the combination of a pivotally mounted lever of non-conducting material, said lever having inserts of conducting material at each end thereof, two solenoids arranged one above the other and each having two equal windings, a plunger functioning as a common core for: the solenoids and consisting of two pieces of magnetic material with a top and intermediate section of non-magnetic material and connecting sections of magnetic material, the plunger being positioned directly beneath the. insert of conducting material in the upper arm of the L-shaped lever, an electric connection from a source of current to the insert in the upper arm of the L-shaped lever, an electric connection from the insert to the upper winding of the upper solenoid, an electric connection between the upper windings of the respective solenoids, a separate electric connection between the lower windings of the respective solenoids, electric connections from.

the lower solenoid to the load, an electric connect-ion from the lower winding of the upper solenoid to the lower conducting insert of the L-shaped lever and an electric connection from the said insert to a ground, a hook member adapted to engage the end of the upper lever arm when same is thrown to raised position by the plunger of the solenoids to break the circuit whereby to hold the lever in such position to stop the flow of current, and a button in operative engagement with said hook device for permitting an authorized person to release same from engagement with the L-shaped lever.

4. In a device for the purposes described,

the combination of an L-shaped lever of nonconducting material, said lever havlng inserts of conducting material at each end thereof,

one of the ends of the lever being hook shaped, two solenoids arranged one above the other and each having two equal windings, a plunger functioning as a common core for the solenoids and consisting of two pieces of magnetic material with a top and intermediate section of non-magnetic material and connecting sections of magnetic material, the plunger being positioned directly beneath the insert of conducting material in the upper arm 01": the L-shaped lever, an electric connection from a source of current to the insert in the upper arm of the L-shaped lever, an electric connection from the insert to the upper winding of the upper solenoid, an electric connection between the upper windings of the respective solenoids, a separate electric connection between the lower windings oi": the respective solenoids, electric connections from the lower solenoid to the load, an electric connection from the lower winding of the upper solenoid to the lower conducting insert of the L-shaped lever and an electric connection from the said insert to a ground.

5. In a bi-polar limiter, the combination of a pair of independent solenoids arranged one above the other, each of said solenoids having two equal windings the upper windings being connected differently in the circuit and the lower windings being connected so that their fluxes are cumulative, a plunger consisting of a common core for the two solenoids, said plunger consisting of an upper and intermediate section of non-magnetic material and two sections of magnetic material extending below each of the sections of non-magnetic material to form an integral device, a pivotally mounted lever arranged above the plunger and having magnetic inserts functioning as contacting elements for the current under normal conditions, electric connections from the windings of the lower ing of the lower solenoid to the lower insert of the pivotally mounted lever, and an electric connection from said conducting insert to a ground.

6. In combination with the device described in claim 5, means for engaging one end of the pivotally mounted lever to hold it in disconnected position until released by an authorized person when it has been moved to a position to break the circuit by the action of the solenoid plunger due either to an overload orto a fraudulent electrical connection applied to the device.

JOHN WV. THOMPSON. 

